More dart2js strong mode cleanup.

pkg/compiler/lib/src/resolution/resolution.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.resolution;
 
 import 'dart:collection' show Queue;
 
 import '../common.dart';
 import '../common/names.dart' show Identifiers;
@@ skipping 756 matching lines @@
       return;
     }
 
     // Check that the mixed in class has Object as its superclass.
     if (!mixin.superclass.isObject) {
       reporter.reportErrorMessage(mixin, MessageKind.ILLEGAL_MIXIN_SUPERCLASS);
     }
 
     // Check that the mixed in class doesn't have any constructors and
     // make sure we aren't mixing in methods that use 'super'.
-    mixin.forEachLocalMember((AstElement member) {
+    mixin.forEachLocalMember((_member) {
+      AstElement member = _member;
       if (member.isGenerativeConstructor && !member.isSynthesized) {
         reporter.reportErrorMessage(
             member, MessageKind.ILLEGAL_MIXIN_CONSTRUCTOR);
       } else {
         // Get the resolution tree and check that the resolved member
         // doesn't use 'super'. This is the part of the 'super' mixin
         // check that happens when a function is resolved before the
         // mixin application has been performed.
         // TODO(johnniwinther): Obtain the [TreeElements] for [member]
         // differently.
@@ skipping 374 matching lines @@
   TreeElements get treeElements {
     assert(_treeElements != null,
         failedAt(this, "TreeElements have not been computed for $this."));
     return _treeElements;
   }
 
   void reuseElement() {
     _treeElements = null;
   }
 }